It is clinically important to determine the role of low level hepatitis B (HBV) and hepatitis (HCV) virus infections in alcoholics with respect to etiology of liver disease using molecular techniques. Alcoholics may be pre-disposed to exposure and acquisition of HBV and HCV due to an abnormal immune response, suppression of the immune response by alcohol, multiple blood transfusions, i.v. drug abuse and in apparent parental exposure. These studies will also improve our understanding of how low level HBV and HBV infections are acquired and why they persist in the alcoholic. Such investigations will eventually help identify patients for anti-viral therapy and therefore may be important in patient care. A pilot study of 67 alcoholics with severe liver disease was performed and we found low level HBV and HGV in approximately 25%. Thus, there was significant risk of exposure and acquisition of low level infection by these two viral agents and they were detected principally by molecular techniques. We plan to greatly expand our studies and determine their functional and molecular characteristics. It is now clear that low level HBV and/or variant infection may be associated with altered viral gene transcription, evolution of pre-S/S and core deletion mutants and development of viral latency at the tissue level. The goals of this grant proposal are the following; i) to assess the prevalence, biologic consequences and molecular characteristics of low level HBV and/or variant infection. Correlations will be made to risk factors such as blood transfusion and i.v. drug abuse as well as histologic type and severity of the liver disease. The biologic behavior of HBV variants compared to "wild-type" virus will be studied in vitro and it is planned to examine the antigenic properties of HBsAg and the changes induced by deletions and mutations in the pre-S/S genes. We will also assess HBV variant gene expression and replication and probe the molecular basis for viral latency. Experiments will be performed showing how the molecular and functional characteristics of the variant viral genomes may be related to the observed serologic and virologic course of infection. 2) Examine the sensitivity, specificity and clinical value of Immuno-PCR to detect low level HBV and HCV antigens in serum and liver and 3) explore the prevalence and role of HCV infection in the pathogenesis of alcohol induced liver injury. In this regard, we will determine if the titer and genotype (I, II, III and IV) of HCV is related to the histologic type and severity of alcohol induced liver disease. The cellular distribution and expression of HCV and related antigens will be examined in liver tissue by in situ hybridization and immunostaining methods. These studies will hopefully provide new information on the presence as well as the biologic behavior of HBV, HBV-variants and HCV in alcoholics based on molecular, structural and functional analysis.